Clamping type bit holders for triangularly shaped cutter bits



April 30, 1963 H. M. STEPHENS ETAL 3,087,713

CLAMPING TYPE BIT HOLDERS FOR TRIANGULARLY SHAPED CUTTER BITS Filed Nov. 10, 1959 MXM- W ma 3 T m 4 5 a a 2 E H W? W 2 7 H. I w mm a a THE/K ATTORNEYS,

Unitcd States Patent Ofilice 3,087,713 Patented Apr. 30, 1963 3,087,713 CLAMPING TYPE BIT HOLDERS FOR TRIANGU- LARLY SHAPED CUTTER BITS Henry M. Stephens and Robert J. Stephens, Montgomery, W. Va., assignors to Marathon Coal Bit Company, Inc., Montgomery, W. Va., a corporation of West Virginia Filed Nov. 10, 1959, Ser. No. 852,008 1 Claim. (Cl. 26233) Our invention relates to certain new and useful improvements in bit holders of the type used in connection with the mining of coal and ore or the like or in such places as requires the use of a bit for cutting the material. It has for its principal object the provision of an improved construction of this character which will be highly eflicient in use and economical in manufacture.

In the mining of coal or ore or the like, a cutter is provided comprising a revolving chain made up of a plurality of links, the chain being gear-driven and generally traveling in a horizontal plane under the control of the operator. Each link in the chain provides a chuck and each chuck provides a bit holder for removably holding the bit in relation to the chain for material-cutting operation. These bits are formed of such material as will withstand the usage to which they are intended to be put. However, due to the hardness of the material and the constant cutting operation per-formed by the cutter bits, the bits generally wear in a relatively short time requiring replacement or resharpening thereof. As the coal cutter is generally under the control of one not ordinarily skilled in mechanics, considerable difliculty is encountered both in time and in labor in the replacement of such bits in the absence of a simple and convenient arrangement to permit quick replacement.

It is therefore one of the objects of this invention to provide a bit holder which is of a relatively simple construction, enabling the operator to change the bit with a minimum degree of effort and time.

Another and equally important object of the invention is to provide a simple and inexpensive arrangement for firmly holding the bit against the vibration to which it is subjected, which would otherwise result in eventually crystallizing the bit, causing the same to break and become unuseful.

Yet another and equally important object of the invention is to provide an arrangement whereby the effectiveness of the bit holder in holding the bit is equally effective for a short or long bit, thus permitting the bit to be periodically sharpened whenever it is required.

A still further object of the invention is to provide a bit holder in which the bit serves to lock itself within the bit holder and wherein the bit may be reversed whenever it is desired.

Other objects will appear hereinafter.

The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed.

The invention will be best understood by reference to the accompanying drawings showing the preferred form of construction, and in which:

FIG. 1 is a perspective view of a chain link and chuck having my improved bit holder associated therewith;

FIG. 2 is a sectional detail view taken substantially on line 22 of FIG. 1;

FIG. 3 is a sectional detail view similar to FIG. 2 but showing a modified form of construction.

To accomplish the several objects of this invention, preferably employ a bit holder of the construction shown in the accompanying drawings. Referring particularly to FIGS. 1 and 2, a chain link is indicated at having spaced openings 11 for connection of the links in chain formation. Each link '10 provides a chuck 12. In the form shown in FIGS. 1 and 2, the chuck 12 is provided with an outwardly extending bore 13. The bores 13 in succeeding links 10 are arranged in staggered relation with respect to each other so that in operation, a relatively wide cut will be made in the material. Such is the common practice in the manufacture of coal cutting apparatuses of the type with which our invention is associated.

Mounted in the bore 13 is the shank 14 of a bit holder 15. The shank 14 is firmly held within the bore 13 by a bolt 16.

The bit holder 15 includes a head 17 providing a socket 18 having opposite corresponding wall portions 19 tapering to form a restricted tail opening 20 and an enlarged head opening 21. The bit 22 is substantially triangular in side elevation and is of a size to permit insertion through the head opening 21 to dispose a flat edge 23 thereof in contact with the adjacent tapered wall 19 and with the long base 23 of the bit flatly engaging the opposite adjacent tapered wall 19.

The tail end of the bit will project a short distance through the tail opening 20 while the lead or head end 24 of the 'bit will extend out beyond the head opening 21 in a position to engage the material to be cut. In this form of construction, we employ a simple arrangement for latching the bit 22 in its socket 18. This means comprises a cylindrical pin 25 formed integral with an L-shaped plate 26, one limb 27 of which is disposed between the head 17 and the chuck 12. The pin 25 projects laterally from the limb 27 through an opening 25' formed in the bit holder 15 and into the socket 18 in blocking position with respect to the adjacent edge of the bit 22. The other limb 28 of the plate 26 enga-ges the adjacent vertical wall 29 of the chuck and is provided with an opening 30 through which a screw bolt 31 is projected and threaded into an opening 32 of the chuck 12 to securely connect the plate 26 to the chuck.

In this form of construction, to place a bit within the bit holder 17, the operator unthreads the bolt 16 to dispose the end portion 33 from engagement with a notch 34 formed in the shank 14. This permits the shank 14 to be withdrawn from the bore 13 a sufficient distance for the bit 22 to clear the latch pin 25 when the bit 22 is inserted in the socket 18. Upon such insertion of the bit 22 in the socket 18, the shank is moved to its innermost position as shown in FIG. 2 and the bolt 16 threaded in a direction to bind the shank within the bore 13, thus firmly latching the bit 22 in the socket 18.

In the form shown in FIG. 3, parts similar to those of the form shown in FIG. 2. are designated by like numerals.

In the form of construction shown in FIG. 3, instead of employing the cylindrical pin 25, We have found it desirable to use a pin 35 which is substantially rectangular in cross section and which provides a tapered edge portion 36 which engages the edge 37 of the bit 22.

In the forms of construction which we have shown in the drawings and which have been described herein, it will be particularly noted that the bits are reversible so that either cutting tip of the bit may be used. The construction permits the bits to be ground for sharpening purposes a considerable number of times without rendering the bit unfit for the purposes for which it is intended.

In operation, when the bit is brought into cutting engagement with the material, it will be noted that the bit bears down upon its respective latch, and as the latch is amply reinforced by surrounding structure, the possibility of damage to the latch is reduced to a mini-mum.

The simplicity of construction of our invention is apparent from the foregoing description and from the drawings, and it is obvious that the same may be manufactured at an economical cost.

By the use of the construction herein described,-the bit may be easily and quickly removed and, if desirable, the notch 34 may be of such a length as to permit the withdrawal movement of the shank from the bore 13 a suflicient distance to permit the bit to clear its latching pin or finger without completely removing the shank from the bore, thus eliminating the possibility of loss or misplacernent of the bit holder.

By virtue of the structure herein described, particularly the fact that the cutting tip of the bit is located below the center of the block, binding in the guides of the bit block is eliminated and the cutting action of the blocks through the coal is more of a pulling action rather than a pushing action.

While we have illustrated and described the preferred form of construction for carrying our invention into effect, this is capable of variation and modification without departing from the spirit of the invention. We therefore do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of such variations and modifications as come within the scope of the appended claim.

7 Having thus described our invention, what we claim as new and desire to protect by Letters Patent is:

The combination with a cutter chain chuck having a bore into which is mounted the shank of a bit holder, said chuck having means for removably securing said shank in the bore of said chuck, said bit holder having a triangularly shaped socket into which is removably positioned a similarly shaped cutter bit, of a holding means for the cutter bit comprising a keeper formed substantially L-shaped to provide right angularly disposed limbs, one of said limbs located between the chuck and said bit holder and the other limb engaging a side wall of the chuck at substantially right angles with respect to said bit holder, said bit holder having an opening formed in a wall thereof and opening into said socket, 'a laterally extending pin integral with said one limb and projecting through said opening into said socket into blocking engagement with an edge portion of said cutter bit for holding the latter in said socket, and means for'detachably connecting said keeper to said chuck.

References Cited in the file of this patent UNITED STATES PATENTS 

